A hybrid impact passive energy absorber has a rigid housing with a mounting base. A housing body includes an interior chamber formed around a chamber axis spanning between two ends of the body. A chamber central portion is partially bounded by first and second central chamber walls. A first chamber end portion extends from the body first end and the first central chamber wall, and a second chamber end portion extends from the body second end and the second central chamber wall. A shaft is disposed within the housing chamber along the chamber axis between the housing first and second ends. An internal mass within the chamber central portion slides on the shaft passing through an internal mass central bore. First and second helical springs surround the shaft on either side of the internal mass, abutting both the chamber end and the internal mass.

To solve a problem, for example, in which holding a movable mass becomes difficult because the spring characteristics of a rubber constituting a basis are set low in order to set the characteristic value at a low value. In a first dynamic vibration absorber including a movable mass that is coupled to a vibration damping target member via an MRE as a first elastic member having elastic characteristics variable with a magnetic field, and being capable of varying a vibration characteristic value of the movable mass by controlling the magnetic field, the dynamic vibration absorber has a second elastic member different from the MRE, and the vibration damping target member and the movable mass are elastically-coupled to each other via the second elastic member.

A tuned mass system has a bulk mass acted upon by an excitation amplitude and a reaction mass coupled to the bulk mass. A resistance-to-motion controlled coupling mechanism associated with the reaction mass is configured to proportionally modulate independent of excitation force such that the relative phase of the bulk mass and the reaction mass is substantially constant throughout an extended range of excitation amplitude. The resistance-to-motion controlled coupling mechanism is a Variable Aperture Reciprocating Reed (VARR) Valve in one embodiment, and operates as a passive mechanism. In other embodiments, active resistance-to-motion controlled coupling mechanisms are employed.

A torsional vibration damping arrangement comprises an input region to be driven in rotation around an axis of rotation and an output region and a first torque transmission path and parallel thereto a second torque transmission path, both of which proceed from the input region, and a coupling arrangement for superposing the torques conducted via the torque transmission paths, which coupling arrangement communicates with the output region, a phase shifter arrangement for the first torque transmission path for generating a phase shift of rotational irregularities conducted via the first torque transmission path relative to rotational irregularities conducted via the second torque transmission path, and a pendulum mass in the phase shifter arrangement and/or in the coupling arrangement.

A torsional vibration damping arrangement comprises an input region to be driven in rotation around an axis of rotation and an output region and a first torque transmission path and parallel thereto a second torque transmission path, both of which proceed from the input region, and a coupling arrangement for superposing the torques conducted via the torque transmission paths, which coupling arrangement communicates with the output region, a phase shifter arrangement for the first torque transmission path for generating a phase shift of rotational irregularities conducted via the first torque transmission path relative to rotational irregularities conducted via the second torque transmission path, and a pendulum mass in the phase shifter arrangement and/or in the coupling arrangement.

The present invention provides a vibration mitigation device which includes a vertically extending housing and a reciprocating assembly coupled with and fully enclosed inside of the vertically extending housing. In accordance with an exemplary embodiment of the present invention, the vibration mitigation device may utilize a tension spring as the biasing member while operating in a pneumatic process, an eddy current dampening process or a hybrid combination of the two dampening processes. For low amplitude, the eddy current dampening process may provide improved vibration mitigation results and for higher amplitudes, the pneumatic process may provide improved vibration mitigation results. Other exemplary embodiments include a vibration damping element that utilizes a compression spring as a biasing member for mitigating vibrations. Further exemplary embodiments provide a vibration damping element that utilizes a compression spring and a tension spring as biasing members for mitigating vibrations.

The present invention provides a vibration mitigation device which includes a vertically extending housing and a reciprocating assembly coupled with and fully enclosed inside of the vertically extending housing. In accordance with an exemplary embodiment of the present invention, the vibration mitigation device may utilize a tension spring as the biasing member while operating in a pneumatic process, an eddy current dampening process or a hybrid combination of the two dampening processes. For low amplitude, the eddy current dampening process may provide improved vibration mitigation results and for higher amplitudes, the pneumatic process may provide improved vibration mitigation results. Other exemplary embodiments include a vibration damping element that utilizes a compression spring as a biasing member for mitigating vibrations. Further exemplary embodiments provide a vibration damping element that utilizes a compression spring and a tension spring as biasing members for mitigating vibrations.

A mechanical system, such as cryogenic refrigerator system, is described. The system comprises two or more axial moving elements generating two or more cyclic forces along parallel axes and a vibration attenuation unit. The cyclic forces are provided with common frequency and certain phase difference between them. The vibration attenuation unit is configured for attenuating vibrations corresponding to two or more modes of vibrations characterized by a frequency corresponding to operation frequency of said two or more cyclic forces.

The dynamic vibration damping system for a building, comprises damping units inserted in housings located in the building façades, or slabs, or partition walls. The damping units comprise a swinging mass (2) sliding horizontally in opposite directions on a swinging plane parallel to the façade or to the slab or to the partition wall when the building vibrates, horizontal springs (3) to absorb the energy generated by the movements of the swinging mass (2), and dampers (4) to damp movements of the swinging mass (2).

A two-dimensional passive energy absorber device has an integral body with a first face and a second face separated by an edge height H. The body includes a platform, a rigid frame surrounding the platform, and a plurality of symmetrical flexible folded beams. The platform and the frame have the same profile shape is arranged to concentrically align, and each of the symmetrical folded beams connects between a frame edge and a platform edge that is not parallel to the frame edge.